Transition member for heat pump appliance

ABSTRACT

A heat pump water heater appliance is provided including a tank defining an interior volume, a sealed system configured for heating water within the interior volume, and a casing. The casing defines an airflow inlet and an airflow exhaust, and the tank and an evaporator of the sealed system are disposed within the casing. A transition member is also provided, including a first end attached to the casing over the airflow inlet and a second end. A passage is defined between the first and second ends. Additionally, a filter tray is removably positioned in the passage of the transition member, allowing, e.g., a user or operator to easily remove and/or replace filter medium supported by the filter tray without disassembling the transition member or any ductwork attached thereto.

FIELD OF THE INVENTION

The present subject matter relates generally to heat pump appliances, or more particularly, to transition members for heat pump water heater appliances.

BACKGROUND OF THE INVENTION

Water heater appliances generally operate to heat water within the water heater appliance's tank to a set temperature. Heat pump water heaters are gaining broader acceptance as a more economic and ecologically-friendly alternative to electric and gas water heaters. Heat pump water heaters include a sealed system for heating water to the set temperature. The set temperature is generally selected such that heated water within the tank is at least hot enough for showering, washing hands, etc. Sealed systems generally heat water more efficiently than electric heating elements and gas burners.

A typical sealed system includes a compressor, a condenser, an expansion device, and an evaporator operating in a closed loop configuration to manipulate a refrigerant. The condenser may be positioned adjacent to the tank of the water heater such that the refrigerant flowing through may exchange energy with water in the tank of the water heater, heating the water. By contrast, the evaporator of the sealed system may be disposed within a casing that such that an airflow may be provided over the evaporator to increase an efficiency of the sealed system.

In certain climates, it may be beneficial to provide such an airflow from remote ambient locations to further increase an efficiency of the sealed system. For example in warm climates, providing an airflow of relatively warm ambient air over the evaporator may further increase the efficiency of the evaporator. Ductwork may generally be attached to the casing to provide such a functionality. However, existing attachment configurations require the ductwork to be disassembled in order to reach an air filter of the heat pump water heater appliance. Alternatively, existing attachment configurations may require the air filter to be inconveniently positioned at a far end of the ductwork, i.e., at the remote ambient location.

Accordingly, a heat pump water heater appliance that allows for connection to ductwork and relatively easy access to an air filter would be beneficial. Further, a heat pump water heater appliance that allows for connection to ductwork and relatively convenient access to the air filter of the heat pump water heater would be particularly useful.

BRIEF DESCRIPTION OF THE INVENTION

Aspects and advantages of the invention are set forth below in the following description, or may be obvious from the description, or may be learned through practice of the invention.

In one exemplary embodiment of the present disclosure, a heat pump water heater is provided. The heat pump water heater includes a tank defining an interior volume and a sealed system configured for heating water within the interior volume of the tank. The sealed system has an evaporator. The heat pump water heater also includes a casing defining an airflow inlet and an airflow exhaust. The tank and the evaporator of the sealed system are disposed within the casing. Additionally, the heat pump water heater includes a transition member including a first end attached to the casing over the airflow inlet and a second end, the transition member defining a passage between the first end and the second end. Moreover, the heat pump water heater includes a filter tray removably positioned in the passage of the transition member, the filter tray configured to support a filter medium such that the filter medium is positioned in an airflow provided to the airflow inlet of the casing through the passage of the transition member.

In another exemplary embodiment of the present disclosure, a transition member for a heat pump water heater is provided. The transition member includes a first end defining a generally semicircular shape, the first end configured to be attached to an airflow inlet defined by a casing of the heat pump water heater. The transition member also includes a second end defining a generally circular shape, the second end configured to be attached to airflow ductwork. The transition member defines a passage extending between the first end and the second end. Additionally, the transition member includes a filter tray removably positioned in the passage of the transition member, the filter tray configured to support a filter medium such that the filter medium is positioned in an airflow provided to the airflow inlet of the casing through the passage of the transition member.

These and other features, aspects and advantages of the present disclosure will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including the best mode thereof to one skilled in the art, is set forth more particularly in the remainder of the specification, including reference to the accompanying figures, in which:

FIG. 1 provides a perspective view of a water heater appliance according to an exemplary embodiment of the present subject matter.

FIG. 2 provides a side elevation view of the exemplary water heater appliance of FIG. 1.

FIG. 3 provides a top plan view of the exemplary water heater appliance of FIG. 1.

FIG. 4 provides a schematic diagram of certain aspects of a water heater appliance in accordance with an exemplary embodiment of the present subject matter.

FIG. 5 provides an exploded view of a top portion of the exemplary water heater appliance of FIG. 1.

FIG. 6 provides a perspective view of a top portion of the exemplary water heater appliance of FIG. 1.

FIG. 7 provides another perspective view of the top portion of the exemplary water heater appliance of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.

Reference will now be made to FIGS. 1 through 3. FIG. 1 provides a perspective view of a water heater appliance 100 according to an exemplary embodiment of the present subject matter. Additionally, FIG. 2 provides a side elevation view of the water heater appliance 100 of FIG. 1, and FIG. 3 provides a top plan view of the exemplary water heater appliance 100 of FIG. 1.

Water heater appliance 100 includes an outer shell or casing 102. Casing 102 generally surrounds a tank 112 (FIG. 4) such that tank 112 is disposed within casing 102. Casing 102 may be formed from a variety of components. As illustrated, casing 102 may include a wrapper 154, a shroud 155, and one or more covers, such as a top cover 156 and a bottom cover 158. Bottom cover 158 may be fastened to wrapper 154, top cover 156 may be fastened to shroud 155, and wrapper 154 may be fastened to shroud 155.

Water heater appliance 100 also includes an inlet or cold water conduit 104 and an outlet or hot water conduit 106, each of which are in fluid communication with a chamber or interior volume 114 (FIG. 4) defined by tank 112. As an example, cold water from a water source, e.g., a municipal water supply or a well, can enter water heater appliance 100 through cold water conduit 104. From cold water conduit 104, such cold water can enter interior volume 114 of tank 112 wherein it may be heated using one or more of an upper heating element 118, a lower heating element 119, and/or a sealed system 120 (see FIG. 4) to generate heated water. Such heated water can exit water heater appliance 100 at hot water conduit 106 and, e.g., be supplied to a bath, shower, sink, or any other suitable feature. As will be understood by those skilled in the art and as used herein, the term “water” includes purified water or alternatively solutions or mixtures containing water and, e.g., elements (such as calcium, chlorine, and fluorine), salts, bacteria, nitrates, organics, and other chemical compounds or substances.

Water heater appliance 100 extends longitudinally between a top portion 108 and a bottom portion 109 along a vertical direction V. Thus, water heater appliance 100 is generally vertically oriented. Water heater appliance 100 can be leveled, e.g., such that casing 102 is plumb in the vertical direction V, in order to facilitate proper operation of water heater appliance 100. A drain pan 110 is positioned at bottom portion 109 of water heater appliance 100 such that water heater appliance 100 sits on drain pan 110. Drain pan 110 sits beneath water heater appliance 100 along the vertical direction V, e.g., to collect water that leaks from water heater appliance 100.

It should be understood, however, that water heater appliance 100 described herein is provided by way of example only and that the present subject matter may additionally or alternatively be used with any other suitable water heater appliance.

As will be explained in greater detail below with reference to FIG. 4, the sealed system 120 includes an evaporator 128 and the water heater appliance 100 includes a fan 129 configured to provide an airflow over the evaporator 128 to increase an efficiency of the sealed system 120. Accordingly, the casing 102 generally defines an airflow inlet 170 at the top end 108 of the water heater appliance 100 along the vertical direction V and an airflow exhaust 172. As is depicted schematically in phantom in FIG. 2, the evaporator 128 may be positioned within the casing 102 proximate to the airflow exhaust 172 defined by the casing 102. However, in other exemplary embodiments, evaporator 128 may alternatively be positioned elsewhere within the casing 102 between the airflow inlet 170 and the airflow exhaust 172 such that an airflow generated by, e.g., a fan (FIG. 4) disposed within the casing 102 may flow from the airflow inlet 170, over the evaporator 128, and out the airflow exhaust 172. For example, in other exemplary embodiments, the evaporator 128 may be positioned within the casing 102 proximate to the airflow inlet 170.

As is also depicted in FIGS. 1 through 3, the exemplary water heater appliance 100 further includes an inlet transition member 174 including a first end 176 and a second end 178, and an exhaust transition member 180 also including a first end 182 and a second end 184. First end 176 of inlet transition member 174 is attached to casing 102 over airflow inlet 170 of casing 102, and first end 182 of exhaust transition member 180 is attached to casing 102 over airflow exhaust 172 of casing 102. Moreover, second end 178 of inlet transition member 174 is configured for attachment to inlet ductwork (not shown), and second end 184 of exhaust transition member 180 is similarly configured for attachment to exhaust ductwork (not shown). Such a water heater appliance 100 may therefore operate more efficiently by utilizing, e.g., relatively warm air from a remote location to exchange heat with evaporator 128. Similarly, such a water heater appliance 100 may not affect the immediately surrounding ambient conditions of the water heater appliance 100, as the cooled air having passed over evaporator 128 may be exhausted to a suitable remote location.

Referring now to FIG. 4, a schematic view of certain components of water heater appliance 100 is provided. As may be seen in FIG. 4, water heater appliance 100 may include sealed system 120 for heating water within interior volume 114 of tank 112. Sealed system 120 generally operates in a heat pump cycle. Thus, water heater appliance 100 is commonly referred to as a “heat pump water heater appliance.” Water heater appliance 100 may additionally include one or more auxiliary heating elements, such as upper heating element 118 and/or lower heating element 119.

Sealed system 120 may include a compressor 122, a first condenser 124, a second condenser 126, and evaporator 128. Additionally, as is generally understood, various conduits may be included to flow refrigerant between the various components of sealed system 120. Compressor 122 and/or evaporator 128 of sealed system 120 may be disposed within casing 102 at top portion 108 of water heater appliance 100 (see FIG. 2). During operation of sealed system 120, refrigerant may flow from first and second condensers 124, 126 to evaporator 128, and from evaporator 128 to compressor 122. For example, refrigerant may enter evaporator 128 as a saturated liquid and may exit evaporator 128 as a saturated liquid vapor mixture. More particularly, an airflow is provided over evaporator 128 using fan 129, and evaporator 128 extracts heat from the airflow and transmits such heat to the refrigerant, increasing a temperature of the refrigerant. Upon exiting evaporator 128, the refrigerant may enter compressor 122, whereby the refrigerant can be compressed such that a pressure and temperature of the refrigerant is increased to become a superheated vapor.

Each condenser 124, 126 may be assembled in a heat exchange relationship with tank 112 in order to heat water within interior volume 114 of tank 112 during operation of sealed system 120. First condenser 124 may be positioned downstream of and in fluid communication with compressor 122, and may be operable to heat the water within interior volume 114 using energy from the refrigerant. For example, the superheated vapor from compressor 122 may enter first condenser 124 wherein it transfers energy to the water within tank 112 and condenses into a saturated liquid and/or liquid vapor mixture. Second condenser 126 may be positioned downstream of and in fluid communication with first condenser 124, and may additionally be operable to heat the water within interior volume 114 using energy from the refrigerant, such as by further condensing the refrigerant.

Sealed system 120 may also include a first throttling device 130 between first condenser 124 and second condenser 126, and/or a second throttling device 132 between second condenser 126 and evaporator 128. Refrigerant, which may be in the form of saturated liquid vapor mixture, may exit first condenser 124 and travel through first throttling device 130 before flowing through second condenser 126. First throttling device 130 may generally expand the refrigerant, lowering the pressure and temperature thereof. The refrigerant may then be flowed through second condenser 126. Similarly, refrigerant, which may be in the form of high quality/saturated liquid vapor mixture, may exit second condenser 126 and travel through second throttling device 132 before flowing through evaporator 128. Second throttling device 132 may generally expand the refrigerant, lowering the pressure and temperature thereof. The refrigerant may then be flowed through evaporator 128, as discussed above.

First and second throttling devices 130, 132 may be any suitable components for generally expanding the refrigerant. For example, in some exemplary embodiments, first and second throttling device 130, 132 may be a Joule-Thomson expansion valve, also known as a “J-T valve.” In other exemplary embodiments, first and second throttling device 130, 132 may be an ejector. In still other exemplary embodiments, a capillary tube, fixed orifice, or other suitable apparatus may be utilized as first and second throttling device 130, 132.

As stated, the water heater appliance 100 may also include upper and lower heating elements 118, 119, which can be any suitable heating elements. For example, upper heating element 118 and/or lower heating element 119 may be an electric resistance element, a microwave element, an induction element, or any other suitable heating element or combination thereof. Lower heating element 119 may also be a gas burner.

Water heater appliance 100 may additionally include a temperature sensor 152. Temperature sensor 152 may be configured for measuring a temperature of water within interior volume 114 of tank 112. Temperature sensor 152 can be positioned at any suitable location within water heater appliance 100. For example, temperature sensor 152 may be positioned within interior volume 114 of tank 112 or may be mounted to tank 112 outside of interior volume 114 of tank 112. Temperature sensor 152 may further be positioned within upper portion 160 or lower portion 162. When mounted to tank 112 outside of interior volume 114 of tank 112, temperature sensor 152 can be configured for indirectly measuring the temperature of water within interior volume 114 of tank 112. For example, temperature sensor 152 can measure the temperature of tank 112 and correlate the temperature of tank 112 to the temperature of water within interior volume 114 of tank 112. Temperature sensor 152 may be any suitable temperature sensor. For example, temperature sensor 152 may be a thermocouple or a thermistor.

Water heater appliance 100 may further include a controller 150 (see also FIG. 1) that regulates operation of water heater appliance 100. Controller 150 may be, for example, in operative communication with sealed system 120 (such as compressor 122, and/or other components thereof), auxiliary heating elements, and/or temperature sensor 152. Thus, controller 150 can selectively activate system 120 and/or auxiliary heating elements in order to heat water within interior volume 114 of tank 112.

Controller 150 includes memory and one or more processing devices such as microprocessors, CPUs or the like, such as general or special purpose microprocessors operable to execute programming instructions or micro-control code associated with operation of water heater appliance 100. The memory can represent random access memory such as DRAM, or read only memory such as ROM or FLASH. The processor executes programming instructions stored in the memory. The memory can be a separate component from the processor or can be included onboard within the processor. Alternatively, controller 150 may be constructed without using a microprocessor, e.g., using a combination of discrete analog and/or digital logic circuitry (such as switches, amplifiers, integrators, comparators, flip-flops, AND gates, and the like) to perform control functionality instead of relying upon software.

Referring now to FIG. 5, an exploded view of certain components of top portion 108 of water heater appliance 100 is provided. As shown, inlet transition member 174 generally includes a lower piece 186 and an upper piece 188, as well as a filter tray 190. Lower and upper pieces 186, 188 of inlet transition member 174 include first and second ends 176, 178, respectively, of inlet transition member 174 and are attached to one another using a plurality of screws 192. More particularly, for the embodiment depicted, lower and upper pieces 186, 188 are attached to one another by a plurality of screws 192 extending through a lower piece flange 194 and through an upper piece flange 196. However, in other exemplary embodiments, lower and upper pieces 186, 188 may instead be attached in any other suitable manner.

Moreover, for the exemplary embodiment of FIG. 5, both airflow inlet 170 defined by casing 102 and first end 176 of inlet transition member 174 generally define a semicircular shape. Additionally, the size of first end 176 of inlet transition member 174 may be substantially the same as the size of airflow inlet 170 defined by casing 102. Accordingly, when first end 176 of inlet transition member 174 is attached to casing 102 over airflow inlet 170 defined by casing 102 using, e.g., a plurality of screws (not shown), a substantially airtight seal may be defined therebetween. One or more suitable gaskets (not shown), such as a rubber or foam gasket, may also be provided to further ensure an airtight seal. It should be appreciated that as used herein, terms of approximation, such as “substantially” or “approximately,” refer to being within a 10% margin of error.

Notably, in certain embodiments, first end 176 of inlet transition member 174 may be attached to casing 102 using existing screw holes and other structure, such that inlet transition member 174 may be configured to retrofit water heater appliance 100 with a length of inlet duct work (not shown).

By contrast with first end 176, second end 178 of inlet transition member 174 generally defines a circular shape. The circular shape of second end 178 of inlet transition member 174 may correspond in size with standard-sized and commercially available ductwork. Accordingly, second end 178 may be easily attached to standard sized ductwork.

A passage 200 is defined by inlet transition member 174 between first and second ends 176, 178 of transition member 174, such that an airflow from inlet ductwork (not shown) may flow through passage 200 to arrive at airflow inlet 170 defined in casing 102. Moreover, filter tray 190 includes a framework 202 configured to support a filter medium (not shown) such that the filter medium is positioned in the airflow provided to airflow inlet 170 of casing 102 through passage 200 of transition member 174. The filter medium supported by framework 202 of filter tray 190 may therefore be positioned to remove unwanted particles and/or other debris in the airflow provided to airflow inlet 170 of casing 102 through passage 200 of transition member 174. In certain embodiments, the filter medium may be a disposable filter medium, or alternatively filter tray 190 may further include permanent filter medium attached to and supported by framework 202 of filter tray 190. Alternatively still, the filter tray 190 may be configured as a disposable filter cartridge supporting the filter medium. In any of the above embodiments, the filter medium may, for example, be configured as one or more layers of a screen material, one or more layers of a fibrous material, pleated paper material, etc. Moreover, as will be discussed in greater detail below with reference to FIGS. 6 and 7, filter tray 190 is removably positioned in passage 200 of transition member 174 when assembled.

Referring still to FIG. 5, exhaust transition member 180 is similarly attached to casing 102 over airflow exhaust 172 (shown in phantom) using, e.g., a plurality of screws 198—although in other embodiments exhaust transition member 180 may instead be attached to casing 102 in any other suitable manner. Additionally, exhaust transition member 180 may similarly be configured to be attached to a length of exhaust ductwork (not shown) at second end 184. Such a configuration may allow water heater appliance 100 to, e.g., exhaust relatively cooler air to a remote ambient location if desired. Notably, however, in other exemplary embodiments of the present disclosure, water heater appliance 100 may not include an exhaust transition member 180, and instead may exhaust air directly to the ambient via the airflow exhaust defined by the casing 102.

Referring now to FIGS. 6 and 7, perspective views of top portion 108 of exemplary water heater appliance 100 of FIG. 1 are provided. More particularly, FIG. 6 provides a perspective view of exemplary water heater appliance 100 of FIG. 1 with filter tray 190 installed, and FIG. 7 provides a perspective view of exemplary water heater appliance 100 of FIG. 1 with filter tray 190 removed.

As shown, the inlet transition member 174 defines a slot 204 for receipt of filter tray 190. Referring particularly to FIG. 6, when filter tray 190 is installed in slot 204 of inlet transition member 174, a filter medium supported by filter tray 190 is positioned in the airflow provided to airflow inlet 170 (see FIG. 5) of casing 102 through passage 200 of transition member 174. By contrast, referring particularly to FIG. 7, filter tray 190 may be removed from slot 204, such that filter tray 190 is no longer positioned in passage 200 of transition member 174, by sliding filter tray 190 along a lateral direction L defined by water heater appliance 102 (see also FIGS. 2 and 3). Accordingly, filter tray 190 depicted in FIGS. 6 and 7 is slidable along lateral direction L into and out of slot 204 defined by inlet transition member 174. Such a construction may allow for easy cleaning and/or replacement of the filter medium supported by filter tray 190, and/or of filter tray 190 itself. Additionally, filter tray 190 depicted includes a handle 206 to assist with such a functionality.

For the embodiment of FIGS. 6 and 7, slot 204 is defined by lower piece 186 and upper piece 188 together, and filter tray 190 is configured to rest on a perimeter ledge 208 (FIG. 7) of lower piece 186 of transition member 174. Further, support bars 210 are provided within lower piece 186 of transition member 174 to offer further support of the filter tray 190.

It should be appreciated, however, that inlet transition member 174 and water heater appliance 100 depicted and described above with reference to the FIGS. are by way of example only, and that in other exemplary embodiments inlet transition member 174 and water heater appliance 100 may define any other suitable configuration. For example, in other exemplary embodiments, airflow inlet 170 defined by casing 102 may define a shape other than a semicircular shape, such as a circular shape, and first end 176 of inlet the transition member 174 may define a suitable corresponding shape. Additionally, although transition member 174 is depicted including distinct lower and upper pieces 186, 188, in other exemplary embodiments, inlet transition member 174 may instead be comprised of a single piece, formed integrally (excepting filter tray 190). Moreover, in other exemplary embodiments, slot 204 may not be positioned proximate a middle portion of transition member 174, and instead slot 204 may be positioned proximate to the first end 176 or, alternatively, proximate to the second end 178 of the inlet transition member 174. Alternatively, in still other exemplary embodiments, the inlet transition member 174 may not define slot 204, and instead may include any other suitable construction for supporting filter tray 190 such that filter tray 190 is removably positioned in passage 200 of inlet transition member 174.

It should also be appreciated that in still other exemplary embodiments, the inlet transition member 174 described herein may alternatively be used with any other heat pump appliance, such as a heat pump water chiller appliance.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other and examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims. 

What is claimed:
 1. A heat pump water heater, comprising: a tank defining an interior volume; a sealed system configured for heating water within the interior volume of the tank, the sealed system having an evaporator; a casing defining an airflow inlet and an airflow exhaust, the tank and the evaporator of the sealed system disposed within the casing; a transition member including a first end attached to the casing over the airflow inlet and a second end, the transition member defining a passage between the first end and the second end; and a filter tray removably positioned in the passage of the transition member, the filter tray configured to support a filter medium such that the filter medium is positioned in an airflow provided to the airflow inlet of the casing through the passage of the transition member.
 2. The heat pump water heater of claim 1, wherein the transition member defines a slot, and wherein the filter tray is slidably received into the slot.
 3. The heat pump water heater of claim 2, wherein the heat pump water heater defines a vertical direction and a lateral direction, and wherein the filter tray is slidable along the lateral direction into and out of the slot.
 4. The heat pump water heater of claim 2, wherein the transition member comprises of a lower piece including the first end and an upper piece including the second end, wherein the lower piece and the upper piece together define the slot.
 5. The heat pump water heater of claim 1, wherein the heat pump water heater defines a vertical direction, and wherein the airflow inlet is defined in the casing at a top end of the heat pump water heater along the vertical direction.
 6. The heat pump water heater of claim 1, wherein the evaporator of the sealed system is positioned within the casing adjacent to the airflow exhaust defined by the casing.
 7. The heat pump water heater of claim 1, further comprising a fan positioned within the casing, the fan configured to provide an airflow from the airflow inlet to the airflow outlet.
 8. The heat pump water heater of claim 1, wherein the filter tray is configured to support a disposable filter medium.
 9. The heat pump water heater of claim 1, further comprising a permanent filter medium attached to and supported by to the filter tray.
 10. The heat pump water heater of claim 1, further comprising an exhaust transition member positioned over the airflow exhaust defined by the casing.
 11. The heat pump water heater of claim 1, wherein the first end of the transition member generally defines a semicircular shape, and wherein the second end of the transition member generally defines a circular shape.
 12. The heat pump water heater of claim 1, wherein the filter tray includes a handle.
 13. A transition member for a heat pump appliance, comprising: a first end defining a generally semicircular shape and configured to be attached to an airflow inlet defined by a casing of the heat pump appliance; a second end defining a generally circular shape and configured to be attached to airflow ductwork, the transition member defining a passage extending between the first end and the second end; and a filter tray removably positioned in the passage of the transition member, the filter tray configured to support a filter medium such that the filter medium is positioned in an airflow provided to the airflow inlet of the casing through the passage of the transition member.
 14. The transition member of claim 13, wherein the filter tray is removably positioned in the passage of the transition member between the first end and the second end.
 15. The transition member of claim 13, wherein the transition member defines a slot, and wherein the filter tray is slidably received into the slot.
 16. The transition member of claim 15, further comprising a lower piece including first end; and an upper piece including the second end, wherein the lower piece and the upper piece together define the slot.
 17. The transition member of claim 13, wherein the filter tray is configured to support a disposable filter medium.
 18. The transition member of claim 13, further comprising a permanent filter medium attached to the filter tray.
 19. The transition member of claim 13, wherein the filter tray is a disposable filter cartridge.
 20. The transition member of claim 13, wherein the heat pump appliance is a heat pump water heater appliance. 